A spokesman for Carlsberg UK said: “As a result of macro-economic circumstances in Russia and Ukraine, and difficult trading conditions in the UK, in order to protect the long-term future of the business, a group-wide pay freeze was announced at the beginning of 2015, which affects all of our colleagues in the UK.

“We have discussed this decision in detail with our colleagues and unfortunately are yet to reach a resolution with our brewery representatives.

“This has resulted in the decision that has been taken by our brewery colleagues. A plan is in place to ensure any potential disruption to supply will be kept to a minimum.

“We remain open to on-going dialogue in order to resolve this matter quickly, in a manner that ensures the long-term future of the UK operation.”